Publications

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within...

In the spring of 2004, the U.S. Geological Survey (USGS) Menlo Park Center Council commissioned an interdisciplinary working group to develop a forward-looking science strategy for the USGS Menlo Park Science Center in California (hereafter also referred to as "the Center"). The Center has been the flagship research center for the USGS in the western United States for more than 50 years...

Prescribed burning has primarily been used as a tool for the control of invasive late-season annual broadleaf and grass species, particularly yellow starthistle, medusahead, barb goatgrass, and several bromes. However, timely burning of a few invasive biennial broadleaves (e.g., sweetclover and garlic mustard), perennial grasses (e.g., bluegrasses and smooth brome), and woody species (e...

Historically, the role of parasites in ecosystem functioning has been considered trivial because a cursory examination reveals that their relative biomass is low compared with that of other trophic groups. However there is increasing evidence that parasite-mediated effects could be significant: they shape host population dynamics, alter interspecific competition, influence energy flow...

Climate in low-latitude wintering areas may influence temperate and high-latitude breeding populations of birds, but demonstrations of such relationships have been rare because of difficulties in linking wintering with breeding populations. We used long-term aerial surveys in Mexican wintering areas and breeding areas in Alaska, USA, to assess numbers of Black Brant (Branta bernicla...

The major histocompatibility complex (MHC) is central to maintaining the immunologic vigor of individuals and populations. Classical MHC class II genes were targeted for partial sequencing in sea otters (Enhydra lutris) from populations in California, Washington, and Alaska. Sequences derived from sea otter peripheral blood leukocyte mRNAs were similar to those classified as DQA, DQB...

To elucidate broad-scale environmental controls of coniferous forest reproduction in the Sierra Nevada, California, we monitored reproduction for 5 years in 47 plots arrayed across a steep elevational (climatic) gradient. We found that both absolute seedling densities (stems

No abstract available at this time

Summary of Conclusions and Recommendations: The levels of mercury contamination found in freshwater fish in Sweden and Finland are similar to those found in such fish in the United States. On the other hand, fish consumption in this country is regarded as generally somewhat less than in the region of Scandinavia. Medical examinations of heavy eaters of contaminated fish have not revealed

Wildfires elicit a perceived need for emergency action to stabilize denuded landscapes. Aerial seeding of rapidly growing nonnative grasses is used routinely in an attempt to control postfire erosion, despite limited scientific basis for its effectiveness and with little consideration for its unintended ecological impacts. As fire size and magnitude have increased in recent decades, so...

This study investigates patterns of plant diversity following wildfires in fire‐prone shrublands of California, seeks to understand those patterns in terms of both local and landscape factors, and considers the implications for fire management. Ninety study sites were established following extensive wildfires in 1993, and 1000‐m2 plots were used to sample a variety of parameters. Data on...

Breeding densities and migration periods of Common Snipe in Colorado were investigated in 1974-75. Sites studied were near Fort Collins and in North Park, both in north central Colorado; in the Yampa Valley in northwestern Colorado; and in the San Luis Valley in south central Colorado....Estimated densities of breeding snipe based on censuses conducted during May 1974 and 1975 were, by...